UNIVERSITI PUTRA MALAYSIA

DISTRIBUTION AND ECOLOGY OF THE MALAYSIAN MAHSEER (GENUS: TOR)

IN KENYIR LAKE, MALAYSIA

LIENG SOPHA

ITMA 1999 1

DISTRIBUTION AND ECOLOGY OF THE

MALA YSIAN MAHSEER (GENUS: TOR)

IN KENYIR LAKE, MALAYSIA

By

LIENG SOPHA

Thesis Submitted in Fulfillment of the Requirements for the Degree of Master of Science in the

Faculty of Applied Science and Technology UNIVERSITI PUTRA MALAYSIA

October 1999

ACKNOWLEDGEMENTS

First and foremost, I would l ike to extend my sincere gratitude to Prof. Dr.

Hj. Mohd. Azmi Ambak, chairman of the supervisory committee, for his invaluable

contribution, advice, tutelage, careful supervision of my Master programme in the

Universiti Putra Malaysia and providing research assistantship from the IRPA

Project (No 50258-13) throughout the course of the study. Without his constant

encouragement this thesis would never have been written .

I am profoundly indebted to the committee members, Assoc . Prof. Dr.

Mohd. Zaki Mohd. Said, and Assoc. Prof. Dr. Sakri Ibrahim, Universiti Putra

Malaysia for their encouragement, invaluable guidance, constructive comments and

critical review of my work throughout the study period.

I wish to express my sincere thanks to the Government of Malaysia for

granting the sponsorship through the Malaysian Technical Co-operation Programme

(MTCP) for the study, particularly Mr. Zainal Abidin bin Abu Hassan and Mr.

Adnan bin Ibon, Training Division for Director General Public Service Department

Malaysia. This thanks is also due to the Malaysian Embassy to Cambodia for

assisting in handling the grant.

I gratefully acknowledge the assistance of the Royal Government of

Cambodia for al lowing me to pursue the study programme smoothly through

placing my service in deputation . I also thank the Ministry of Forestry,

11

Fisheries and Agriculture. I would l ike to extend my sincere gratitude for their

assistance in one way or another particularly to :

Mr. Ly Kim Han, Director, Department of Fisheries, Cambodia

Mr. Nao Thuok, Vice Director, Department of Fisheries, Cambodia and

National Project Director of the Freshwater Capture Fisheries

Management Project,

Mr. Touch Seang Tana, former Project Director,

Mr. Nicolaas van Zalinge, C.T.A./Senior Fishery Biologist for the

Freshwater Capture Fisheries Management Project.

Heartfelt acknowledgement and gratitude go to Assoc. Prof. Dr. Noor Azhar

Shazil i , Dean of Graduate School who helped me in every possible way. I 'd l ike to

express my sincere thanks and gratitude to Prof. Dr. Law Ah Theem for thoroughly

editing the manuscripts . The appreciation are also to Assoc. Prof. Dr. Lokman

Hussain, Dr. Khalid Bin Hj . Sarno, Dr. Abol-Munafi A.B . and Mr. Liew Hock

Chark, University Putra Malaysia who have helped and guided me in one way or

another. I 'd like to thank to Mr. Esa bin Mohd Daim, Mrs. Arbaiyah Mohd Isa and

Mr. Abdul Aziz Bahsir for their administration. I'd to thank to Mr. lalal K.C.A. for

consultation, Mr. Shahreza Md Sheriff for translating the abstract from English to

Malaysian language and Mr. Olubunmi Akins for editing the manuscripts.

I wish to extend my appreciation to all staffs of the UPM, Terengganu

Campus, including Mr. A. Manaf, Hj . Hosni lalauddin, Hj. Sukiman Sengat and Mr.

III

Sulaiman, Mrs. Marhaini , Mr. Muhammad Embong, Mr. Johari , Mr. Ismai l , Mr.

Sharol, Mr. Muhamad Ibrahim, Mr. Fazil, Mr. Wan Awang, Mr. Rashid, Mr. Rosli ,

and Mr. Kasim for their innumerable assistance and co-operation in the sample

field, laboratory and logistics. The acknowledgement goes also to Miss Rose, Zira,

and Lina for their co-operation and assistance.

My sincere thanks are also due to all my post-graduate friends and well

wishes including Mr. Zulkamal M.R., Mr. Seang Meng, Joni H., Subarjo, Rozihan

M. , M. Yusoff, Musse G.H. , Razarudin 1., Dinh T.D. , Liem P.T. Miss Aishah Y. ,

Miss Nazlin R.M.S . , Miss Suhaila who have assisted me in providing different

inputs directly or indirectly which contributed to the accomplishment of this work.

Finally, the heartfelt gratitude goes to my parents for their encouragement,

untiring guidance and support. The gratitude is also to my grandma who frequently

guided me when she was stil l alive. I 'd l ike to thank to my parents in laws for their

support and encouragement. Special thanks are for my wife, Mrs. Meng Phall ine for

their patience, encouragement, and understanding throughout the study period. My

daughter, Sopha Var Leak also deserves appreciation for motivation.

IV

TABLE OF CONTENTS

"ERPUST AWN !liLT AN ABDUL SAMAC UNiVERSlTl PUTRA MALAYSIA

Pages

ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 11

LIST OF FIGURES LIST OF TABLES LIST OF PLATES

. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 0 • • • • • • • • • • • • • • • • • • • • • •

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .

x

xii xi i i

ABSTRACT ABSTRAK

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 0 ' • • • • • • • • •

xiv xvii

LIST OF ABBREVIATIONS . . .. . . . . . . . . . . . . " . , . . . . . . . . . . . . . . . . . . . . . . . . . xx

CHAPTER

I

II.

III.

INTRODUCTION

Background of the Study Statement of the Problems 7

Significance of the Study . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Objectives of the Study ... .... ..... ............. .... ..... ..... .... 14

DESCRIPTION OF THE STUDY AREA 1 5

General Features . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Flora and Fauna . . . . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Limnological Profi le Sampling Sites

LITERA TURE REVIEW

Taxonomy

Fish Distribution

Habitat Selection Microhabitat

v

23

26

27

27

32

36

37

IV.

Macrohabitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Feeding Ecology

MAHSEER DISTRIBUTION AND HABITAT PROFILE

Introduction

39

40

43

43

Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Mahseer Distribution and Abundance . . . . . . . . . . . . . . . . . . . 48

Habitat Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Water Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1

Water Velocity

Transition Zone

Pool

R iffle

Run

Substrate

Aquatic Plants and Leaves of Tree . . . . . . . . . . . . . . . . . .

Shade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ' " . . . . . . . . . . . . .

Effects of Man

Tree Trunk

Water Chemistry

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mahseer Distribution and Abundance . . . . . . . . . . . .. . . . . .

Tor tambraides

Tor sora .................................................. .

Habitat Profile . . . ' " . . . . . . . . . . . . . . . ' " . . . . . . . . . . . . . . . . . . . . . .

Water Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Water Velocity

Transition Zone, Pools, Riffle and Run . . . . . . . . . .

Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aquatic Plants and Leaves of Trees

VI

51

51

52

53

53

55

55

55

55

56

56

58

58

58

64

65

65

65

66

66

67

V.

Shade

Effect of Man

Tree Trunk Water Chemistry

Water Temperature Water Transparency pH Conductivity Dissolved Oxygen Hardness of Water

67

67

68

68

68

69 69 70

70 70

Calcium and Magnesium . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1 Discussions

Mahseer distribution

Habitat Profi le Water chemistry

Water Temperature Water Transparency pH Conductivity Dissolved Oxygen Hardness of Water

Calcium and Magnesium . . . . . . . . . . . . . . . . . . . . . . . . . . .

HABITAT UTILIZATION OF TOR SORO (C &V)

Introduction Objectives Materials and Methods

Microhabitat ' " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Avai labil ity of Microhabitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Microhabitat Analysis

Statistical Analysis

VII

72 72

76 8 1

8 1

8 1 8 1 82

82

83

83

85

85 88

89 89

93

94

95

VI.

Results

Macrohabitat Analysis 96

97

... "'crohabitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Water Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 97

Water Velocity

Substrate

102

105

Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ' " 1 09 Fish Aggregation Species Association Distance from Fish Position to

1 14

1 1 7

the Edge of Stream . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 8 Macrohabitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 9

Discussions 1 23

FEEDING ECOLOGY OF THE MALAYSIAN MAHSEER 1 28

Introduction 1 28

1 3 1 Materials and Methods

Result

Food Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 1 Feeding Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '" 1 32

Relative Length of Gut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 32

Foo d compo sit io n

Feeding Apparatus

Relative Length of Gut Discussions

1 33 133 1 35 1 38 1 39

V1ll

VII. SUMMARY AND CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 46

Summary

Conclusion

Further Study

BIBLIOGRAPHY

APPENDICES

1 46

1 53

1 55

1 57

1 74

VITAE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 97

IX

LIST OF FIGURES

Figure Page

1 . Map of the Peninsular Malaysia Showing the Location of Kenyir Lake 1 6

2. Map of Kenyir Lake

3 . Monthly Rainfall Fluctuation i n Kenyir Lake.

1 7

1 9

4. Map of Kenyir Lake Showing the Malaysian mahseer Distribution 59

5. Water Level Fluctuation in Kenyir Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6. Water Depth Used by, Available to, and Preferred by Tor sora at Sg. Buluh Nipis IT and Sg. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

7. Depth Used by Tor sora of Different S ize Classes at S g. Buluh Nipis II and S g. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0 1

8 . Water Velocity Used by, Available to, and Preferred by Tor sora at Sg. Buluh Nipis II and Sg. Mandak II . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 03

9. Water Velocity Used by Tor sora of Different S ize Classes at Sg. Buluh Nipis IT and Sg. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 05

1 0. Substrate Used by, Available to, and Preferred by Tor sora at S g. Buluh Nipis IT and Sg. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 06

1 1 . Different Use of Substrate in Pre-monsoon and in Monsoon at Sg. Buluh Nipis IT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

. 1 2. Different Use of Substrate in Pre-monsoon and Monsoon at Sg. Mandak II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 08

1 3 . The Use of Cover by Tor sora Compared with Cover Available at Sg. Buluh Nipis IT and Sg. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 09

1 4. Distance from Fish Focus Point to Nearby Cover at Sg . Buluh Nipis IT 110

1 5 . Distance from Fish Focus Point to nearby Cover at S g. Mandak II 1 1 0

1 6. Aggregation of Tor sora in Pre-monsoon and in Monsoon at Sg . Buluh Nipis II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 4

x

17. Aggregation of Tor sora by Fish Size Categories at Sg. Buluh Nipis IT 1 15

18. Aggregation of Tor sora in Pre-monsoon and in Monsoon at

Sg. Mandak IT 1 16

19. Aggregation of Tor sora by Fish Size Categories at Sg. Mandak IT 1 16

20. Association of Tor sora with other Fish Species at Sg. Buluh Nipis IT

and at Sg. Mandak IT 1 17

2 1. Distance from Fish Focus Point to the Edge of Stream at Sg . Buluh Nipis IT . . .. . . ...... ...... .............. ............. 1 18

22. Distance From Fish Focus Point to the Edge of Stream at Sg . Mandak IT . . . . . . . .. . . . . . .. .. . .. . . . . . ....... ............ ......... 1 19

23. Macrohabitat Use of Tor sora by Habitat Types at Sg. Buluh Nipis IT. 1 20

24. Macrohabitat Use of Tor sora by Habitat Types at Sg. Mandak II 1 21

25. Macrohabitat Use of Tor sora by Fish Size Categories at

Sg . Buluh Nipis IT 1 2 1

26. Macrohabitat Use of Tor sora by Size Categories at Sg. Mandak IT 1 22

27. Percentage of Food Items Encountered in Gut Contents of Tor sora 1 34

28. Number of Guts Contained Food and no Food 1 34

xi

LIST OF TABLES

Table

1 . Morphometric Index Data of the Lake Kenyir

2. Limnoiogical Prof i le of Lake Kenyir

3 . Fish Abundance Categories

Pages

1 8

24

50

4. Location of the Malaysian Mahseer were Distributed in Lake Kenyir 60

5. Mahseer Distribution and Characteristics of their Habitat 6 1

6 . Distribution and Abundance of Tor tambroides in Lake Kenyir 63

7 . Distribution of Microhabitat Used and Available (Depth, and Water Velocity), Between and within Sites, and Distribution of Fish Sizes at Sg. Buluh Nipis IT and Sg. Mandak IT. . . . . . . . . . . . . .. . . . . . . . . . . . .. 99

8. Range of Depth and Velocity that have a Suitability Index � 0.5 Based on Site-Specific Use and Preference Model that have been Normalised to 1.0. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 99

9. Seasonal Use and Availability of Depth and Velocity Distribution at Sg. Buluh Nipis IT and Sg. Mandak IT. . . . . . . . . . . . . . . . . . .. 1 02

1 0. Relation between the Use of Cover and Fish of Different Size

Categories at Sg. Buluh Nipis II ............... ......... .... III

II. Relation between the Use of Cover and Fish of Different Size Categories at Sg. Mandak IT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

12 . Relation between Fish and the Use of Cover by Season at Sg . Buluh Nipis IT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 3

1 3. Relation between Fish and the Use of Cover by Season at Sg . Mandak IT .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 113

14. Relative Length of Gut (R .L.G.) of Tor soro (C & V) Caught from Sg. Buluh Nipis IT and Tor tambroides

(Bleeker) Caught from Sg. Berang. . . . . .. . . . .. . . . . . ... . . . .. . ... 1 38

xii

LIST OF PLATES

Plates

1 . Tor tambroides (Bleeker) (left) and Hampala macrolepidota van Hasselt (right) in Kenyir Lake . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1

2. Juvenile Tor tambraides in Kenyir Lake 44

3. Juven i le Tor sora in Lake Kenyir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4. Under Water Observation of Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5 . Direct Visual Observation of Fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

6. Transition Zone

7. Pool Zone

8. Riffle Zone

9. Run Zone

1 0 . Activities of Data Collection at the Field

1 1 . Photo Showing that both the Juvenile Tor sora (above) and Tor tambroides (below) have no Teeth on the lower and upper

52

53

54

54

9 1

Jaw and both Fish Species have Thick Lips. 1 36

12 . Photo showing that both the Juvenile Tor sora (right) and Tor tambroides (left) have Pharyngeal Teeth on the lower and upper Pharyngeal Arch. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 36

1 3 . S ide view of the Mouth of Juvenile Tor sora (left) and Tor tambraides (right) showing that both Fish S pecies have the Same Protracted, and Sl ightly Inferior Mouth . 1 37

1 4 . Photo of the Alimentary Canals of Juvenile Tor sora (the photo above) and Tor tambroides (the photo below ) showing that the Stomachs of both Fish Species had a S lightly Extended Tube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 37

xiii

Abstract of the thesis presented to the Senate of Utliversiti Putra Malaysia in Fulfilment of the requirements for the Degree of Master of Science.

DISTRIBUTION AND ECOLOGY OF THE MALAYSIAN MAHSEER IN LAKE KENYIR, MALAYSIA.

by

LIENG SOPHA October 1999

Chairman: Prof. Dr. Hj. Mohd. Azmi Bin Ambak Faculty: Faculty of Applied Science and Technology

A study on distribution and ecology of the Malaysian mahseer (Tor sora

Cuvier & Valenciennes and Tor tambroides Bleeker) was carried out in lotic and

lentic habitats in Lake Kenyir, Malaysia.

The fish distribution and habitat profi le of the Malaysian mahseer were

studied to investigate the ecological condition and their relationship with the

environment and to determine the present spatial distribution and abundance in the

lake system. The results showed that there is a habitat selection by fish of different

sizes, (fingerl ing 2.0 - 7.0 cm, juveniles 7.1 - 20.0 cm and adults >20.0 cm TL) in

relation with size of stream, water depth, current velocity, substrate, water

temperature, water transparency, dissolved oxygen, and habitat types.

The adults of Tor tambroides were most abundant in deeper parts or pools in

upstream reaches of large streams (26-60 m width) of Sg. Tembat and Sg.

Terengganu and medium-sized stream ( 1 2-25 m width) of Sungai Kiang. The

XIV

juvenile were found in all sizes of sampled streams in the lake. The adult of T. sora

were found in less abundance in small and medium-sized streams of Sg. Buluh

Nipis n, Sg. Mandak I and n, Sg. Siput, and Sg. Lancang. However, the juveniles

and fingerlings were mostly found in the small stream reaches and were most

abundant at water depths ranging from 10 to 187 cm with velocity ranging from 1 to

118 cm.s·l. The adults occurred in habitats where the water depth was about 5.4 m

and current velocity ranged from 1 to 66 cm.s·l. The fingerling and juvenile of both

species were frequently found in streams where pools represented from 3 to 9%,

runs 5 to 32%, riffles 61 to 91 % of the total area. The fingerlings and juveniles were

mostly found in habitats where boulders were predominant followed by bedrock,

sand, gravel, cobble and pebble. The adults mostly occurred in habitats where the

substrate comprised of boulders and rock. The young mahseers were frequently

found in clear-running water, while the adults occurred in slow-running and more

turbid water as compared to the young mahseer. The temperature profile ranged

from 23.0 to 2S.3°C. the dissolved oxygen varied from 6.7 to 8.8 mg.rl. The water

hardness of the mahseer habitat nullifies the effect of toxic metals to the fish.

The microhabitat and macrohabitat analysis of habitat use and preference of

T. soro in the two small stream reaches of Sg. Buluh Nipis IT and Sg. Mandak IT

showed that T. soro preferred depths between 52 em and 120 em and water velocity

between 0 and 35 cm.s·l. Different size classes of T. sora used different mean

depths at both sites. The seasonal use of depth and velocity by T. sora were

significantly different at both sites (p<O.OS). T. sora preferred sand and gravel as

substrate. T. sora preferred cover up to 70% and the fish of all size had similar

preference for cover at both sites (p>O.OS). T. sora generally aggregated in groups

xv

ranging from 1 to 7 fish and were found to associate with Acrossocheilus dearatus

(C & V) and Osteochilus vittatus (C & V). The adults of T. sora were found in

pools . The juveniles were quite well spread in all habitat types, pools , runs and

riffles, while the fingerlings were most abundant in riffle habitat.

It was found that T. soro fed mainly on algae and other available fauna and

flora at the stream of Sg. Buluh Nipis II. Examining their feeding apparatus , the

teeth of T. sora (7.0 -26.0 cm in TL) and T. tambroides ( 17 .0 - 25 .0 cm in TL) were

not developed on the lower and upper jaw, but there is a presence of pharyngeal

te€th on the upper and lower pharyngeal arch. Their mouths were protracted and

slightly inferior. The l ips of both fish species were thick. Being a typical cyprinid,

both fish species had no conventional stomach and possessed an extended long

intestine. The fish employed suction feeding in adaptation with their feeding

apparatus. The relative length of gut (R.L.G.) for the T. sora with the size range

from 7.0 to 26.0 cm in total length has been found to vary from the lowest 0.77 to

the highest 2.85. The value of R.L.G. for T. tambraides with size ranging from 1 7.0

to 25.0 cm in total length also varies, ranging from l.11 to 2 .50. Both fish species

were omnivores as evident from gut content analysis and the relative length of gut .

I t could be concluded that the mahseer is a highly territorial fish species . The

physical and chemical parameters are significant in determining spatial distribution

and abundance of the Malaysian mahseer and also important in the application of

habitat-based management of the mahseer population in Lake Kenyir.

XVI

Abstrak tesis dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi syarat untuk mendapatkan Ijazah Master Sains.

TABURAN DAN EKOLOGI MAHSEER MALAYSIA DI TASIK KENYIR, MALAYSIA

Oleh

LIENGSOPHA

October 1999

Pengerusi: Prof. Dr. Hj. Mohd. Azmi Bin Ambak

Fakulti: Fakulti Sains Gunaan dan Teknologi

Satu kajian terhadap taburan dan ekologi ikan kelah (T. sora Cuvier &

Valencies dan T. tambroides Bleeker) telah dijalankan di habitat lotik dan lentik di

Tasik Kenyir, Malaysia

Kajian terhadap taburan ikan serta profil habitat ikan kelah telah dijalankan

untuk mengkaji keadaan ekologi ikan kelah serta perhubungannya dengan

persekitaran dan untuk menentukan taburan spatial dan kelimpahan terkini di dalam

sistem tasik. Hasil kajian mendapati terdapat pemilihan habitat oleh ikan yang

berbeza saiz (fry 2.0 - 7.0 em, juvenil 7.1 - 20.0 em dan dewasa >20.0 em panjang

total) terhadap saiz anak sungai, kedalaman, kelajuan arus, substrat, suhu air,

kejemihan, oksigen terlarut dan jenis habitat.

Ikan Kelah dewasa ban yak terdapat di kawasan yang lebih dalam atau lubuk

di bahagian hulu (20-60 em lebar) sungai Tembat dan Sungai Terengganu serta di

kawasan sungai yang mempunyai kelebaran sederhana ( 1 2-25 em lebar) di Sungai

XVlI

Kiang. Ikan juvenil dijumpai dalam pelbagai SaIZ di kawasan persampelan .

Kel impahan ikan dewasa adalah rendah di sungai keeil dan sederhana di sungal

Buluh Nipis IT, Sungai Mandak I dan IT, Sungai S iput dan Sungai Laneang.

Walaubagaimanapun, kebanyakkan ikan fri dan juvenil oi dapati di sungai keei l dan

kerap terdapat di kawasan yang mempunyai kedalaman berjulat di antara 1 0 hingga

1 87 em dengan kelajuan arus di antara 1 hingga 1 1 8 em. s·1 • Ikan dewasa dijumpai

di habitat dengan kedalaman 5 .4 em dengan kelajuan arus berjulat dari 1 - 66 em.s·l .

Fri dan juvenil bagi kedua-dua spesies kerap dijumpai di kawasan sungai di mana

lubuk mewakili di antara 3 hingga 9%, runs diantara 5 hingga 32%, jeram di an tara

61 hingga 9 1 % daripada keseluruhan kawasan. Fri dan juvenil banyak dijumpai di

habitat di mana terdapat banyak balak diikuti dengan kawasan berbatu, berpasir,

gravel , cobble dan pebble. Ikan dewasa dijumpai di kawasan air perlahan dan keruh

berbanding dengan ikan yang muda yang kerap dijumpai di kawasan air jemih .

Seeara keseluruhan, suhu di kawasan kajian berjulat diantara 23 .0 hingga 25 .3 °C

dengan nilai oksigen terlarut di an tara 6.7 hingga 8 .8 mgTI .

Berdasarkan analisis mikrohabitat dan makrohabitat bagi T. sora di kawasan

sungai kecil di Sungai Buluh Nipis II dan Sungai Mandak II, T. soro lebih memilih

kawasan yang mempunyai kedalaman di antara 52 em hingga 1 20 em dengan

kelajuan arus di antara 0 hingga 35 em.s· l . Kajian juga menunjukkan bahawa saiz

ikan yang berbeza menggunakan kawasan min kedalaman yang berbeza di kedua­

dua kawasan. Pemil ihan kawasan kedalam dan arus bagi setiap musim oleh T. sora

di dapati mempunyai perbezaan yang bererti di kedua-dua kawasan (p<0.05). T.

sora lebih memilih kawasan berpasir dan gravel sebagai bahan substrat. T. sora dari

XVlll

pelbagai SaIZ di dapati gemar tinggal di kawasan yang mempunyal tempat

berlindung yang hampir mel iputi 70% di kedua-dua kawasan (p>0.05) . T. sora

kebiasaannya tinggal berkumpulan dalam kelompok di antara 1 hingga 7 ekor

dalam satu kumpulan bersama dengan Acrassocheilus dearatlls (C & V) dan

Osteochilus vittatus (C & V). T. sora dewasa dijumpai di kawasan lubuk manakala

ikan juvenil lebih tersebar hampir ke semua habitat seperti jeram dan lubuk

manakala anak jej ari banyak terdapat di kawasan jeram.

Ikan T. sora memperolehi makanan daripada alga dan lain-lain flora dan

fauna yang terdapat di kawasan Sungai Buluh Nipis ll. Ikan T. sora (7 .0 - 26.0 em

panjang total) dan T. tambraides ( 1 7.0 - 25.0 em panjang total) mempunyai mulut

inferior dengan bibir yang tebal . Ia tidak mempunyai gigi di bahagian rahang at as

dan bawah tetapi mempunyai gigi faring di bahagian at as dan bawah kawasan

faring. Kedua spesies ini tidak mempunyai perut tetapi mempunyai usus yang

panjang. Spesies ikan ini memakan seeara menghisap sebagai satu adaptasi terhadap

struktur mulutnya. Panjang relatif usus T. sora berjulat di an tara 0.77 hingga 2.85

bagi ikan yang bersaiz di antara 7 .0 hingga 26.0 em panjang total . Panjang relatif

usus T. sora berjulat di antara 1 . 1 1 hingga 2.50 bagi ikan yang bersaiz di an tara 17.0

hingga 25 .0 em panjang total .

Seeara keseluruhannya, ikan kelah adalah ikan yang bersifat territorial .

Taburan dan kel impahan ikan kelah ban yak bergantung kepada parameter fizikal

dan kimia. Pengetahuan parameter in i sangat penting dan berguna dalam

pengurusan populasi ikan kelah berdasarkan habitat di Tasik Kenyir.

XIX

LIST OF ABBREVIATIONS

°C Degree Celsius

% Percentage

uS/cm Microsimon/ centimetre

cm Centimeter

C.V. Cuvier and Valenciennes

E East

E"" Expectation Frequency

FFRC Freshwater Fisheries Research Centre

GPS Global Position System

ha Hectare

Ko-::;, Kilogram

m meter

m3 Cubic meter

mg Milligram

mg/J Milligram per litter

N North

0 Observation Frequency

ppm Parts per million

R .L.G. Relative Length of Gut

SD Standard Deviation

xx

Sg.

SL

TL

TWL

US$

Malaysian language abbreviation for "Sungai" means River

Standard Length

Total Length

Top Water Level

Unit of the Currency of the United States

xxi

CHAPTER I

INTRODUCTION

Background of the Study

Fishes are important to mankind as a source of protein (Biswas , 1 993,

Philip et al . , 1 993). In Malaysia fish and other seafood are the major diet which

makes up at least 20% of the per capita consumption of all protein. This is almost

equal to the amount of protein taken from other meats such as poultry, pork, beef

and mutton which together contribute about 23% of the required protein (Ishak et

al . , 1 986). Thus, fish is a vital source of food.

Fish is not only a source of vital protein to the population, it also provides

employment for the rural people, gaining some of foreign exchange and creating

opportunity for recreation (Khan, 1 992). In 1 996, the fisheries sector produced

1 ,239,434 tones of total fish production valued at RM3 .84 bill ion contributing

about 1 .54% to the national Gross Domestic Product (GDP) . In this total

production , the marine fisheries landed 1 , 1 25 ,689 tones or 90.90% of the total

production, the inland fisheries landed 3,683 .2 1 tones or 0.30% of the total

production and aquaculture production was 109,062 tones or 8 .80% of the total

production . Exclusively, ornamental fish production ornamental 278 ,462,210

2 pieces. These fisheries provided direct employment to 99,578 people consisting of

79,616 fishermen and 19,902 aquaculturist. This employment constituted about

1.18% of the total labor force in the country (DoF, 1998). Thus the fisheries sector

plays a significant role in providing protein and employment, especially in rural

areas, as well as supports the country economic growth .

Although recreational fisheries have not been well developed, Malaysia has

the potential for recreational fisheries development, both marine and inland. The

existing recreational fishing is sti ll in the form of some nature preservation, the

development and management of sport fish is very rudimentary. In fact, its potential

is enormous (Ambak, 1984). The Malaysian coastline is 3,400 km with about

160,000 square nautical miles of inshore and offshore (Anon, 1989). However the

development of marine sport fisheries needs more precaution and more complicated

than freshwater. On the other hand, freshwater sport fisheries have received high

popularity in the world. Besides this , many natural or man-made freshwater water

systems in Malaysia exist in many forms with existing-sport fish that can be

promoted to sport fisheries. Reservoirs estimatedl y cover an area of about 91,680 ha

(Anon, 1983). In Peninsular Malaysia alone, there are 15 major reservoirs (DoF,

1982). Disused mining pools cover 16,680 ha (Arumugam, 1991). There are more

than 100 river systems in the country (Baluyut, 1983). Large tracts of freshwater and

peat swamp forests cover some 2.5 million ha (Parish and Davies, 1991). These are

the available natural resources potential. With these natural resources, recreational

fisheries have existed in many places and anglers throughout the country have

caught many species. There are many media including New Straits Times, Rod and

Line, and Pancing discussed about fisheries recreation, experiences, guides,